Apparatus for treating ore pulp with gas



Mar; 3, 1925.

Filed April 2,1923

INVENTOR la tented Mani 1925 I v I UNITED STATES PATENT OFFICE.

WILLIAM E. GREENAWALT, or DENVER, COLORADO.

APPARATUS FOR TREATING ORE PULP WITH GAS.

Application filed April 2,

To all whom it mug concern: Be it known that I.,'1LL1.\M E. GREEN-AWA'LT, a citizen of the United States, re-

siding in the city and county of Denver and State of Colorado, haveinvented certain new and useful Improvements in Apparatus for TreatingOre Pulp with Gas, of which the following is a specification.

The invention has as its object the effective treatment of ores,especially ores of copper containing precious metals, with gases,especially corrosive gases, such as chlorine or sulphur dioxide- Theeffective treatment of finely ground ore with a corrosive gas, hasalways presented a difficult problem, and it cannot be said to have beeneffectively solved. Rotating barrels have been generally used, butbarrels are expensive to install, expensive to operate, and areveryunsatisfactory, owing largely to the fact that the treatment isintermittent, and that the gas cannot be progessively applied.

Agitation in a stationary tank is quite simple air is used. as theagitating gas. No ditiicult impregnation problem is involved in thatcase, and compressedair can easily be introduced into the bottom of thetank to agitate the liquid and then be allowed to escape at the top.\Vith corrosivegas agitation and impregnation it is entirely different.The gas has to be used to agltate and to impregnate the liquid, andconditions have to be arranged so that none of the gas, or but verylittle of it, is wasted. The gas should be progressively applied, sothat all, or nearly all, is consumed. In addition to this, if ore sludgeis treated, the gas has to be applied in such a way as to keep the oreparticles under continuous agitation, to get the desired extraction ofthe metals, and also to prevent the ore from settling, and thus cloggingthe apparatus and making it inoperative. 'If clogging occurs, except atrare intervals, the entire apparatus would become impractical.

. One object of this invention, therefore, is to provide an apparatusfor the treatment of ore pulp, in which the gas can be pro gressivelyapplied to agitate and impregnate the liquid, and so that the gas willbe progressively consumed.

At the present time, as also in the past, the application of corrosivegas to fine ore pulp, has had to be'applied in small units,

and when large capacity was desired, the

not be effectively 1923. Serial No. 629,360.

The capacity of barrels rarely exacharge, and the per day rarely ex-Besides, the could applied, and usually inferior results are obtained,

Another object of" this invention is to prov1de an apparatus of largeunit capacity, exceeding, if need be, units of 1000 tons of indefinitelymultiplied. chlorination and similar coed ten tons of ore at amount ofore treated cecds to tons.

ore per day, and in which the operator will ,or atomizer; Fig 3 beingthe section and Fig. 4 the plan; and Figs. 5 and 6 are details ofanother form of agitator, or atomizer; Fig. 5 being the section, andFig. 6 the plan. y

In the drawings, 1 is a treator, taken as a whole, and is preferablycomposed of a number of units,'or tanks, 1". 1", and 1. The number oftanks, in practice, will depend on the amount and the nature of thematerial to be treated. The treator 1, is adapted to contain a liquid,or ore sludge, and to confine a gas over the liquid, and preferablyarranged so thatthe liquid in the respective tanks can flowprogressively from one tank to the next of the series, throughcommunicating passages 2, which .will ordiis rather coarse, so that theascending gas would be unable to elevate it to any considerable height.It is also desirable to have communicating passages 3 in the upperportion of the tanks, so that the gascan flow progressively from onetank to the next. in its passage through the treator. from the gas inlet4 towardthe gas outlet 5. Each tank composing the treator is providedwith an exhauster (3 which exhausts the gas from the upper portion ofthe re spective tanks and forces it into the lower portion, throughthepipes 7. These pipes are arranged so that the gas from the exhausterscan be delivered to the same tank from which it was exhausted, or to thead-- j acent tank, or a portion to both tanks. Suspended within eachtank and submerged in the liquid is a rotary agltator, or atomizer, 8,so designed and arranged that the gas delivered into the lower portionof the tank will pass through the a itator in its ascent through theliquid and be distributed in finely divided particles into the surrounding liquid in thetank.

The agitators may be of the form shown by 8*, or by 8*. Either form willgive good results. The material to be treat-ed w11l largely determinethe details-of the agitator. The agitators will usually be made of acidresisting metal, such as antimonial lead] The shaft 9, will usually alsobe covered with lead to protect the steel from the corrosive action ofthe gas and liquid. A stufling box, 10, where the shaft enters the tank,will prevent any leakage of gas. The stuliing box is made removable andlarge enough so that when it is removed, the agitator may be withdrawnfrom the tank through the opening. An exhauster 11 creates a flow of gasthrough the various tanks, and maintains a suction inwardly, so thatthere Wlll be no escape of corrosive gas to contaminate the atmospherein the vicinity of the apparatus and thus make annoying conditions forthe workmen. The ore, which will usually be in the form of a thicksludgeor fine powder, is introduced into the treator through the inlet12. \Vhether the ore is dry or in the form of a thick sludge, it will benecessary to add more water, or solution, to give it the properconsistency for the most effective results in the treator.

Under these conditions, it is desirable to' first treat the liquid withthe gas so that the liquid will be charged with the gas before it comesin contact with the ore. This saves time, besides, the charging, ortreating, of the liquid with the gas, when the liquid is free, orcomparatively free of insoluble particles, is very much easier than tostart the impregnation of the ore pulp in the treator. For this reasonit is desirable tohave a relatively large tank, or imcontinuoustreatment of the gas.

way, all the prclimlnary reactions with solupregnator 14, adapted tocontain a relatively large pool of the liquid, and means adapted so thatthe liquid of the pool can be under In this ble matter in the liquidwill take place in the impregnator, and the liquid will be charged withthe gas, as it enters the treator,

I and thus efiect a saving of time and expense,

in the more expensive treatment in the treator. The impregnator 14,consists essentially of a tank adapted to contain a pool of liquid andto confine a gas over the pool, and has a gas inlet 15 and a gas outlet16. The .gas inlet communicates with the gas producer 17, and the gasoutlet communicates with the gas inlet 4, of the treator 1. \Vithin theimpregnator' 14 is ahorizontal rotary sprayer 18, so arranged that theliquid of the impregnator is continuously sprayed into the gaseousatmosphere above the liquid. This sprayer throws a considerable portionof the liquid against the sides of the tank, at a higher elevationthanthe normal level of the liquid, so that the spray, charged with the gas,falls into the duct 19, and thus producesa circulation of the liquidwithin the impregnator, so that all the liquid in the impregnator is atall times treated with the gas, and can be drawn inacontinuous streaminto the treator 1. The liquid flows into the impregnator 14 in acontinuous stream through the pipe 20, and overflows through the weirarrangement 21, which maintains a' constant liquid level in theimpregnator 1 1. 'The treated liquid, overflowing in a continuous andregulated stream through the weir 21, from the impregnator 14, ismixedwith the fine dry ore, or thick ore sludge, introduced through thepipe 12, and the mixture then flows into the treator through the pipe13. A weir overflow 22, in the treator 1,'maintains a constant liquidlevel in the treator. The overflow, or outflow, is so arranged that ifthere are any heavy sand particles in the pulp which cannot readily belifted to the weir, they can flow out through the pipe 23, near thebottom, in regulated amounts. A small continuous stream'of sand andliquid will, in such cases, flow out through the pipe 23, to take theheavier particles of suspended matter, while the main stream willoverflow through the. weir 22.

The exhauster 11, creates a flow of gas from the gas generator 17through the entire system; this prevents escape of gas, and

overcomes the annoyances when the gas is used under pressure. It isdesirable to treatthe liquid in the impregnator 1 1 with the strongestgas, and then pass the excess on through the apparatus, preferably, inthe same direction as the mainstream of material being treated. Theadvantage of this is, that most of the gas is consumed in preparing theliquid, and in the first reactions with the ore pulp, and once thesemore energetic reactions have been completed, it is quite easy to keepthe pulp saturated, or charged, with the gas. In this way, the reactionsstart at once, and the treatment is effective from start to finish.

While the exhauster 11 creates a general flow of gas through the entiresystem, the

tanks, to pass through the rotary atomizers iii made a little largerthan the atomizers, so that when 1t 1s desired to renew or repair an Theaction of the atomizers can best bedescribed by referi'ing tothe-details, in Figs; 3, 4, 5, and 6. Referring to Figs-3 and 4: the gasintroduced through the bottom of the tankr'ises through the liquid, andas it ascends it enters the rotary hooded and perforated atomizer 8, sothat a continuous stream of gas and ore pulp passes through theperforations while the atomizer is rotating at' the rate of from 200 to400 R. P. M. This thoroughly agitates and impregnates the liquid, or orepulp, and maintains the pulp charged with the gas. Referring to Figs. 5and 6: the operation is a little different, although the result is muchthe same. The gas and some of the pulp enters the atomizer 8", and theatomizer, rotating at a speed of from 200 to 400 R. P. M., ejectsthemixture of gas and liquid through the discharge passages 24 into thesurrounding liquid in the tank, and in thisway the gas is atomized inthe liquid while the liquid, or pulp, is under continuous agitation,both on account of the rotation of the atomizer and on account of theascending atomized gas.

It is evident, that when corrosive gases are used, such as chlorine orsulphur dioxide,

and quite certainly also in such cases where an acid solution is used,the construction of the agitator, or atomizer, is of importance. Neitherthe atomizer itself nor that, portion of the shaft that is within thetank, can be constructed of the ordinary material, such as iron. It ison this account that the apparatus presents some advantages inconstruction. The atomizers8 or 8 may be easily cast of some acidresisting material, such as antimonial lead, and the portion of thesteel shaft inside of the tank can readily be covered with lead. Thisdoes not present any unusual difliculty. The shaft outside of the tank,as also the bearings and driving mechanism, may be constructed as usualand with the ordinary materials. A stuffing box 10 is arranged in thecover of the tank to prevent the leakage of air in, or of possibleleakage of gas out. This stuffing box is atomizer the stuffing box 10,can be unscrewed from the top of the tank, and the entire agitatingmechanism lifted vertically with a block and tackle and removed throughthe opening.

In an arrangement of the sort described, where there is a main stream ofgas flowing through the apparatus above the liquid and secondary streamscirculated through the liquid in the various tanks composing theapparatus, diificulty is likely to develop on account of the possible orprobable uneven volumes of handled by the respective It is largely onthis account exhausters. that the cominumcatlng gas passages 3 are"provided: for. If'the volume of gas handled by the respectiveexhausters 6 is not the same, or the consumption of gas in therespectivetanks is different, an equalization effect is obtainedthrough, the comn'iunicating gas passages throughtthe entire system,while, nevertheless, the main stream of gas is always from the gas inlettoward the gas outlet. The exhauster 11 is supposed to work only underenough suction to prevent the escape of gas from any portion of theapparatus, and to always maintain'only a slight suction inwardly.

A brief description of theapparatus will now be given in its applicationto the treatment of ores, with a chloride solution, containing, say,copper, gold, andsilver, and

possibly lead and other metals. The extraction of gold from copper oresby a wet process has always presented great difficulties, and in mostcases these difficulties have been practically insurmountable.

I The impregnator 14 and the treator 1 maybe presumed, in starting, tobe filled with leaching solution obtained from previous operations, andit may be assumed as an acid chloride solution. The chlorine cells 17,in which common salt is, decomposed into chlorine and caustic soda, arestarted to operate, and. the chlorine'is flowed, by means of theexhauster 11, into the impregnator 14, where the solution is chargedwith the gas and where the preliminary solution reactions take place,suclras the conversion of ferrous iron to ferric iron. If there is goldin the ore, the solution in the impregnator 14 is saturated withchlorine. The rotary sprayer 18, which may be considered as a number oflead discs about. a foot in diameter mounted on a horizontal shaft, and

rotatinoat about 1000 R. .lKML, fills the gas 'space a ove the liquidwith adnist and fine spray, which effectively charges the-sprayed liquidwith tlurgas, and thus the entire pool of liquid becomes charged withthe gas. A portion of the liquid is sprayed against the side of thetank, and drops into the duct 19 and produces a mild circulation of theentire mass, and thus the entire pool of liquid is always char ed. ortreated, with the gas. The charged liquid flows from the impregnator 14into the pipe 13, where it is mixed with the ore from the pipe 12, andthe mixture of ore and liquid, as also the stream of excess gas, flowsinto the treator 1. The gas absorbed by the liquid in the impregnator isquickly consumed, and to make the from above the liquid, and introducedinto the lower portion of the liquid, and in its ascent through the.liquid, or pulp, it isatomized and distributed by the atomizers 8 and 8and thus the liquid ischarged with the gas, in the treator, as rapidlyas the gas 'is consumed in acting on the ore pulp, or other gasconsuming compounds in the liquid. The agitation helps to dissolve themetal values, and effectively prevents any settling of ore particles.If, for any reason settling should occur and the agitators becomestopped, the ore could easily be agitated by increasing the volume ofgas, temporarily, and thus clear the obstruction. In the way described,the ore is treated for several hours, and the stream of pulp through thetreator is regulated so that the rate of flow is proportioned to. theextraction desired, as determined by experience. The time of treatmentwill usually vary from one to three hours. It will usually be desirableto heat the liquid;,this can be done by means of the steam or hot waterpipes in the impregnator 14. The excess gas, after the entire treatment,will probably be small: it is preferably exhausted into anotherimpregnator, similar to 14, filled with fresh solution, where it isquickly and completely absorbed. The treated ore pulp, in which themetals are now .in solution, mostly in the form of chlorides, isthenflowed into a separator tank, where the liquid is separated from thegangue, and the gangue wasted. The metals may be precipitated from theclarified solution by any of the well known -methods, and the depletedsolution returned to the impregnator, to be passed through anothercycle, as the one described.

The application of the apparatus, as applied, for example, to thetreatment of 0x1- 3 dized copper ore with sulphur dioxide, will now. bedescribed, reference being made to Fig. 2, more particularly, lbuthaving also in mind the other figures. It is well known that coppersulphite, produced from leaching copper ore with sulphurous acid, is notVery soluble in water, and hence, the ore usually requires severaltreatments with the separator 29, which may be presumed to besomething'after the order of a Dorr thickener, where the clear coppersolution is separated from the insoluble residue. The insoluble residue,without any particular washing,-is then flowed from the separator 29into thetreator T No. 2, through the pipe 34, where it isagain treatedwith a sulphur dioxide solution practically free from copper, so' thatmore copper can be brought into solution, and this is continued untilthe copper is sufficiently extracted. The barren residue may then bewasted through the pipe 41. The clear copper solution, issuing from theseparator 29, is flowed into the precipitator 30 where the copper isprecipitated, in whole or in part, by any of the well known methods,such, for example, and preferably, by electrolysis or hydrogen sulphide.By either of these methods an amount of acid is regeneratedcorresponding tothe amount of copper precipitated. A portion of the.depleted copper solution may be returned to the impregnator 14, throughthe pipe 31, or to the treator T No. 1, and another portion, or thewhole, as the case may be, is flowed, through the pipe 33, into theimpregnator26 which is like the one shown by 14, Fig. 1, in which theexcess gas is absorbed by the solution. Since the solution is entirelydepleted of gas, recovery of the excess gas by the solution, is notdifficult. The solution, now having absorbed the excess gas from treatorT No. 1, is then flowed into imprcgnator 14*, where the solution issaturated with fresh gas. The outflowing charged solution from theimpregnator,

mixed with the ore residue from the separator 29, is again treated in TNo. 2, as described in treator T No. 1. .The excess flows into theimpregnator 26*, where it is absorbed as described for 26. The treatedore pulp flows into separator 37, where the clear copper solution isseparated from the insoluble residue. If the copper is sufiicientlyextracted, the residue may be wasted if not, the cycle is repeated. Theclear copper solution, no'wcontaining some of the copper as sulphite,and some as sulphate, due to the regenerated acid from the previousrecipitation, in precipitators 40, and the solhtion, erated in acid,returned to the residue, applied to fresh ore, or wasted, as theconditions may determine.

As an illustration of the large unit capacities of which theapparatus'is capable depleted in copper and regen-' of being installed,tanks 10 feet square and 20 feet high, having a depth of liquid of 15feet may be considered. Each tank would hold about 45 tons of pulp andnot less than 10 tons of ore. lttherc are ten tanks in Series, andthetime of ore treatment is 2.4 hours, the capacity, per day of 24 hours,would be about 1000 tons of ore.

The treator portion of this invention-may be considered as amodification, or continuation in part, of the invention shown in myPatents No. 1,340,826, May 18, 1920, and No. 1,374,500, April 12, 1921.The impregnator 14, or modification of it, is more fully described -inmy Patent No. 1,353,995, Sept. 28, 1920, and in my pending ap lication,Serial No. 485,884, filed July 12, l921.

the liquid. If properly designed, and if the liquid is not too deep, theexhauster 6 1 may be dispensed with, and the flow of gas fromtheupperportion of the tank through the impregnator 8 induced by the suction ofthe impregnator alone.

Obviously, the gas, instead of passing from the first treator (Fig. 2)into the second treator, may be applied direct to the second treator, TN o. 2. This would'be desirable, for example, in the treatment of copperores containing other metals, such as gold, silver, cobalt, nickel,etc., in which it would be desirable to leach out the copper from theore, or a portion of it, before applying free chlorine to extract theremaining metals.

I claim:

1. In metallurgical apparatus, a tank adapted to contain a pool ofliquid and to con ne a gas over the pool, means arranged for flowingliquid through the tank and mingling it with the pool, suction means forflowing gas through the tank over the liquid, suction 'meansforexhausting a portion of the gas from above the liquid and introducing itinto-the'lower portion of the tank through 'a stationary pipe, and meansarrangedin the lower portion of the tank for subdividing the gas in itsascent through the liquid.

2. In metallurgical apparatus, a tank ada ted to contain a pool ofliquidand to con e a gas over the pool, means arranged for flowing liquidthrough the tank and mingling it with the pool, means for flowing gasthrough the tank over the pool of liquid, means for withdrawing aportion of the gas from above the liquid and introducing it below thesurface of the liquid through a stationary pipe, and a hollow rotarmember open at its lower portion and having discharge passages suspendedwithin the tank and submerged in the liquid which receives the gas inits. ascent through the liquid and ejects it in finely divided particlesinto the surrounding liquid.

in the tank- 3. In metallurgical apparatus, a tank ada ted to contain apool of liquid and to con no a gas over the pool, means arranged forflowing liquid through the tank, means for flowing gas through the tankover the liquid, a hollow perforated rotary member open at itslower-portion sus ended within the tank and submerged in t e liquid, andmeans for withdrawing gas from above the liquid and introducing it intothe lower portion of the tank through a stationary pipe, said pipe androtary member being arranged-so that the gas in its ascentthrough theliquid will pass through the rotary said member and be ejected in finelydivided parlticles into the surrounding liquid in the tan r.

4. In metallurgical apparatus, a tank adapted to containa relativelylarge pool of liquid and to confine gas over the liquid, a hollow rotarymember having discharge passages mounted on a vertical axis andjournaled within the tank, means arranged for flowing liquid, throughthe tank and mingling it with the pool, means for flowing gas throughthe tank over the liquid, means for withdrawing gas from above theliquid and introducing it in the lower portion of the tank through astationary pipe, pipe and rotary member being arranged so that the gasin its ascent through the liquid will pass through the dischargepassages of the rotary member, and means for maintaining a slightsuction inwardly in thetank. I

5. In apparatus fortreating liquids with gases, a tank adapted tocontain a relatively large pool of liquid and to confine gas over theliquid, a. rotary member journaled on a vertical shaft suspendedwithinthe tank and submerged in the liquid, suction means for flowing gasthrou' h the tank over the liquid, means for with% the gas fromabov'ejthe liquid and introducing it in the lower portion of the tankthrough a stationary pipe, said pipe and rotary member being arranged sothat the 'journaled on vertical shafts suspended with in'the respectivetanks and submerged in the liquid, means for flowing liquidprogressively through the respective tanks, suction means for flowinggas through the respective tanks over the liquid, means for withdrawinggas from above the liquid in the respective tanks and introducing itthrough stationary pipes into the lower portion of the tanks, said pipesand rotary members being so arranged that the gas in its ascent throughthe liquid will be atomized by the respective rotary members.

7; In metallurgical apparatus, a series of tanks adapted tocontain'liquid and to confine gas over the liquid and arranged withcommunicating passages between the tanks for-the gas and the liquid,rotary members mounted on vertical 'axes suspended within the respectivetanks and submerged in the liquid, means for flowing a stream of liquidprogressively from one tank to the next of rawing a portion of theseries, suction means for flowing a stream of gas progressively throughthe tanks over the liquid, and means for withdrawing gas from the mainstream above the liquid and introducing it in the lower portion of therespective tanks to be subdivided by the rotary member in its ascentthrough the liquid.

8. In metallurgical apparatus, 'a series of tanks adapted to containliquid and to confine gas over the liquid and arranged withcommunicating passages between the tanks for the liquid, means forintroducing gas into the tanks above the liquid, exhausters forwithdrawing gas from above the liquid of the respective tanks andintroducing it below the surface of the liquid, and means arranged forequalizing the gas pressure in. the respective tanks due to variationsin the operation of the respective exhausters.

9. In metallurgicalapparatus, a series of tanks adapted to contain poolsof liquid and to confine gas over the liquid, means for exhausting gasfrom above the liquid of they respective tanks and introducing it in thelower portion of the tanks through stationary pipes, means forsub-dividing the gas in its ascent through the liquid in the respectivetanks, and means arranged to flow the gas and liquid progressivelythrough the respective tanks.

10. In metallurgical apparatus, a series of tanks adapted to containpools of liquid and to confine gas over the liquid, means for exhaustinggas from above. the liquid of the respective tanks and introducing it inthe lower portion of the tanks through stationary pipes, means forsubdividing the gas in its ascent through the liquid in the respectivetanks, and means arranged to flow the gas and the liquid progressivelythrough the respective tanks in the same direction.

11. In metallurgical apparatus, a. creator comprising a. series of tanksadapted to contain pools of liquid and the .material to be treated andto confine gas over the liquid, an impregnator comprising a separatetank adapted to contain a pool of liquid and to confine gas over theliquid, means for treat ing the liquid in the impregnator with the gas,means for flowing both the liquid and excess gas from' the impregnatorinto the series of tanks comprising the treator, and means for treatingthe liquid and the ma.- terial in the respective tanks with the gas bywithdrawing the gasfrom above the liquid of the respective tanks andintroducing it in the lower portion of the tanks.

12. In metallurgical apparatus, a series of tanks communicating with oneanother and adapted to contain ore pulp and to confine gas over thepulp, an impregnator communicating with the series of tanks and adaptedto impregnatea liquid with a gas, means for introducing ore pulp and theimpregnated liquid into the ,series of tanks, means for introducing theexcess gas from the impregnator into the series of tanks, means forwithdrawing gas from above the liquid of the respective tanks andintroducing it in the lower portion of the tanks, and suction means forflowing the gas through the liquid impregnator and series of tanksoverthe liquid.

13. In metallurgical apparatus, a series of tanks adapted'to containpools of liquid and to confine gas over the pools, means for flowing astream of liquid through the tanks and mingling it with the respectivepools, means for withdrawing gas from above the surface of the liquidand introducing it into the lower portion of the respective pools,rotary members in the respective tanks adapted to agitate the liquid andto subdivide the gas introduced in the lower portion of the tanks in itsascent through the liquid, and

means for progressively advancing the ex-' cess gas from one tank of theseries to the next.

'14. In metallurgical apparatus a tank adapted to contain liquid and toconfine gas over the liquid, a hollow gas distributing member within thetank submerged in the liquid having a vertical fluid inlet in its lowerportion and horizontal fluid discharge passages in its upper portion andadapted to receive separate streams of gas and ii uid and to eject amixture of gas and liqui in substantially horizontal streams into thesurrounding liquid in the tank, and means for delivering gas from thetank above the liquid into the lower portion of the hollow gasdistributin member.

15. In metallurgical apparatus a series of tanks communicating with oneanother and adapted to contain liquid and to confine gas over theliquid, hollow gas distributing members within the tanks submerged inthe liquidhaving vertical fluid inlets in their lower portions andhorizontal fluid dis charge passages in their upper portion said hollowgas distributors being adapted to receive separate streams of gas andliquid and to eject a mixture of gas and liquid in substantiallyhorizontal streams into the surrounding liquid in the tanks, and meansfor delivering gas from above the liquid of one tank into the hollow gasdistributing memberof the next tank of the series.

16. In metallurgical apparatus, a tank adapted to contain a relativelylarge pool of liquid and to confine gas over the liquid, a hollow gasdistributing member within the tank submerged in the liquid having avertical fluid inlet in its lower portion and horizontal fluid dischargepassages extending outwardly from its central portion toward theperiphery said hollow gas distributing member being adapted to receiveseparate streams of gas and liquid-and to eject a mix;

ture of gas and liquid into'the surrounding liquid in the tank, meansfor flowing liquid through the tank and mingling it with the pool, andmeans for delivering gas from the 5 tank above the liquid into theinterior of the hollow gas distributing member.

17. In metallurgical apparatus, a tank adapted to contain liquid and toconfine gas over the liquid, a rotary member journaled 1 Within thetankand submerged in the liquid eject it into the surrounding liquid inthetank, and a stationary pipe communicating with the gas in the upperportion of the tank and with the interior of member.

WILLIAM E; GREENAWALT.

the rotary

